1. Field of the Invention
The present invention relates to a field of semiconductor integrated circuit (IC) manufacturing, and more specifically, to an apparatus for and a method of forming an ultra-abrupt semiconductor junction profile.
2. Discussion of Related Art
Continual shrinking of a complementary metal-oxide-semiconductor (CMOS) integrated circuit (IC) as exemplified in the well-known Moore's Law requires a formation of an ultra-abrupt semiconductor junction. In a case of a PMOS transistor in the CMOS IC, a source/drain region and its extension must have a very high Boron concentration with an extremely abrupt Boron profile. In the analogous case of an NMOS transistor in the CMOS IC, the source/drain region and its extension must have a very high Arsenic or Phosphorus concentration with an extremely abrupt Arsenic profile.
A p+/n semiconductor junction may be formed by ion implanting a p-type dopant, such as Boron, into an n-type substrate, such as Arsenic-doped Silicon, followed by annealing the substrate at over 1,000 degrees C. The NMOS transistor requires a high anneal temperature to activate the dopant. Unfortunately, the use of such a high temperature results in a significant out-diffusion of the dopant into the substrate in the PMOS transistor.
Thus, a need exists for an apparatus of and a method of forming an ultra-abrupt semiconductor junction profile.